“Based on the market prices during the attack’s preparation and the difficulty of the blocks the attacker produced, we estimate the attacker spent between 0.5-1 BTC to perform the attack,” Lovejoy explained.

“The total value of the block rewards the attack received is 13825 VTC (~0.44 BTC). Given the attack was likely not profitable to perform based solely on block rewards, the motivation for the attack is not certain.”

To gain control on the Vertcoin’s network, the attackers targeted crypto exchange Bittrex first.

Suggested articles

“I contacted Bittrex, Vertcoin’s most prominent exchange, to recommend they disable the Vertcoin wallet on their platform once it became clear an attack was in progress, which they subsequently did,” he noted in the latest report.

Lessoned learned

Created in 2014, Vertcoin is one of the many Bitcoin forks available in the market today. The blockchain of the coin was attacked last year in a similar style, resulting in the theft of $100,000 worth VTC coins.

“Vertcoin was previously 51% attacked in Dec 2018 and has since changed its proof-of-work algorithm to Lyra2REv3,” he stated.

This change of algorithm turned out to be really effective, which eventually prevented the recent attempt for the attack.

“Given the reorg was just deeper than 600 blocks (Bittrex’s confirmation requirement for VTC), it is possible that Bittrex was the original target, but the double-spend portion attack was aborted due to Bittrex disabling their wallet before the fork could be released,” lead maintainer stated.